Polyvinyl chloride (PVC) resins generally have the following drawbacks: 1. Poor processability; 2. Poor impact strength at low temperature; 3. Poor heat stability; 4. Poor toughness at low temperature. At present, a variety of methods have been invented to improve the drawbacks of polyvinyl chloride resins, such as: adding additives to improve the processability of polyvinyl chloride resins; adding anti-impact modifiers to improve the anti-impact property of polyvinyl chloride resins at low temperature; adding heat stabilizers to improve the heat stability of polyvinyl chloride resins. However, the problem of the toughness of polyvinyl chloride resins at low temperature has not been well solved so far. And the problem of the toughness of polyvinyl chloride resins has become the major barrier for the development of polyvinyl chloride resins. For example, in the field of materials of the pipes for supplying water, polyvinyl chloride pipe materials have been gradually replaced by polyethylene (PE) pipe materials, mainly because bend deformations of polyvinyl chloride pipe materials buried under ground happen when terrain changes by time. As the toughness of polyvinyl chloride at low temperature is low, polyvinyl pipe materials will be easily broken by a slight bend; however, as the elongation at break for PE is high, PE pipe materials will not be broken even when the PE pipe materials bend because of the change of terrain. Therefore, for long-distance water supplying systems, PE pipe materials are usually preferred. Moreover, the major reason that wood materials cannot be replaced by polyvinyl chloride products is that polyvinyl chloride products will be easily cracked while inserting nails, and the fundamental reason for such phenomenon is the low elongation at break and the poor toughness of polyvinyl chlorides. Besides, cracking of the welding angles of the polyvinyl chloride doors and windows happens easily in winter when temperature is very low, which is also mainly because of the low elongation at break and the poor toughness of polyvinyl chlorides.
For a long period of time, there's a big misunderstanding in the field of modifying polyvinyl chlorides: mistakenly, it is considered that increasing the notch impact strength of polyvinyl chlorides is the same as increasing the toughness of polyvinyl chlorides; and mistakenly, it is considered that increasing the impact strengths of polyvinyl chlorides will increase the toughnesses of polyvinyl chlorides, thus increase the low temperature resistances of polyvinyl chlorides, therefore solve the problem of polyvinyl chloride pip materials such as cracking. Therefore, acrylates anti-impact modifiers (anti-impact ACR), methyl methacrylate-styrene-butadiene copolymers (MBS) anti-impact modifiers are usually used to increase the impact strengths of polyvinyl chlorides. However, although anti-impact ACR and MBS can largely increase the notch impact strengths of polyvinyl chlorides, they can hardly effectively improve the toughnesses of polyvinyl chlorides, especially the toughnesses under low temperature, which is not satisfying. Thus, currently, the elongations at break of polyvinyl chloride resins are not the same as or close to that of polyethylene, and the nail-holding abilities of polyvinyl chlorides are not the same as that of wood material.